EP 1820869 A1 20070822 - Spring-use heat treated steel wire
Title (en)
Spring-use heat treated steel wire
Title (de)
Wärmebehandelte Stahldraht für Feder Verwendung
Title (fr)
Traitment termique d'un fil d'acier pour ressort
Publication
Application
Priority
- JP 2005022418 W 20051130
- JP 2004346996 A 20041130
- JP 2004346995 A 20041130
Abstract (en)
The present invention provides spring steel used for spring steel wire achieving both high strength and cold coilability and spring steel wire, that is, spring steel containing, by mass%, C: 0.45 to 0.70%, Si: 1.0 to 3.0%, Mn: 0.05 to 2.0%, P: 0.015% or less, S: 0.015% or less, N: 0.0015 to 0.0200%, and t-O: 0.0002 to 0.01 and further limiting Al‰0.01% and Ti‰0.003%. Further, it is characterized by satisfying the following regarding the cementite-based spherical carbides present at an observed plane, an occupied area ratio of grains with a circle equivalent diameter of 0.2 µm or more of 7% or less, a density of presence of grains with a circle equivalent diameter of 0.2 to 3 µm of 1/µm 2 or less, and a density of presence of grains with a circle equivalent diameter 3 µm or more of 0.001/µm 2 or less, having an prior austenite grain size number of #10 or higher and a residual austenite of 15 mass% or less, and having an area ratio of poor regions with a small density of presence of cementite-based carbides of a circle equivalent diameter of 2 µm or more of 3% or less.
IPC 8 full level
C22C 38/00 (2006.01); C21D 8/06 (2006.01); C21D 9/52 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/22 (2006.01); C22C 38/28 (2006.01); C22C 38/60 (2006.01); F16F 1/06 (2006.01)
CPC (source: EP KR US)
C21D 8/06 (2013.01 - EP US); C21D 8/065 (2013.01 - KR); C21D 9/02 (2013.01 - KR); C21D 9/525 (2013.01 - EP KR US); C22C 38/001 (2013.01 - EP KR US); C22C 38/002 (2013.01 - EP KR US); C22C 38/02 (2013.01 - EP KR US); C22C 38/04 (2013.01 - EP KR US); C22C 38/22 (2013.01 - EP KR US); C22C 38/28 (2013.01 - EP KR US)
Designated contracting state (EPC)
DE SE
DOCDB simple family (publication)
EP 1820869 A1 20070822; EP 1820869 A4 20100113; EP 1820869 B1 20151007; BR PI0514009 A 20080527; BR PI0514009 B1 20151103; EP 2465963 A1 20120620; EP 2465963 B1 20151007; KR 100851083 B1 20080808; KR 20070005013 A 20070109; US 10131973 B2 20181120; US 2008279714 A1 20081113; WO 2006059784 A1 20060608; WO 2006059784 A9 20060810
DOCDB simple family (application)
EP 05814388 A 20051130; BR PI0514009 A 20051130; EP 12158986 A 20051130; JP 2005022418 W 20051130; KR 20067025105 A 20061129; US 63022205 A 20051130